The interannual variation of summer droughts in Xiangxi of Hunan Province is investigated,and the underlying causes for the drought events are explored,based on the drought index(CI) of Xiangxi,as well as the NCEP/NCAR reanalysis data and NOAA SST data.The CI is calculated by daily temperature and precipitation data from 1960 to 2013 recorded by 8 meteorological stations in Xiangxi.The results show that severe drought events occurred in summer of year 1961,1972,1981,1994,2009,and 2013,and the droughts are closely related to the mid-and high-latitude circulation anomaly patterns,and circulations at low latitudes and the tropics as well.The thermal external forcing near the Philippines from West Pacific to the Bay of Bengal,associated with the rainfall anomalies,is able to lead to the anomalous movement of the western Pacific Subtropical high,which probably results in the drought events.When the rainfall is positive with stronger than normal convection near the Philippines,the subtropical high moves northward anomaly and controls the Xiangxi area with less rainfall,then the drought will easily occur in Xiangxi.